Final results of the European Parliament polls in Ireland on Tuesday showed Prime Minister Bertie Ahern's governing Fianna Fail overtaken for the first time ever by the main opposition party in a major election.

Fine Gael, which has only been in power in coalition governments, won five of Ireland's 13 seats in the European Parliament, against four for Fianna Fail, and is now seen as a threat to Ahern's ambitions for a third term in office, mid-way though his second.

But its success was clouded by a surge in support for Sinn Fein, the political wing of the Irish Republican Army (IRA), which saw its share of the vote increase by five percent to 11.1 percent.

Sinn Fein, striving to become a political force in both the Irish Republic and Northern Ireland, won one seat, while the Irish Labour party won one and independents two. The Greens lost both of the seats they won in the previous EU election, held in 1999.

"It was very good to actually win a national election," said Frank Flannery, Fine Gael's director of elections and leading strategist, told RTE public radio.

"I think it is the first time ever, Fine Gael came first in a major contest like the European elections, winning the majority of the seats," he said.

Founded in 1933, Fine Gael has formed several governments -- most recently under prime ministers Garret FitzGerald in the 1980s and John Bruton in the 1990s -- but always in coalition.

Even though it won most seats and saw its support grow by over three percent to 27.8 percent, its share of first preference votes was still below Fianna Fail's 29.5 percent. The governing party suffered a drop in support of more than nine percent since the 1999 election.

Votes were still being counted after local elections held at the same time as the EU poll, and Flannery predicted that Fianna Fail and Fine Gael would end up neck and neck in terms of local council seats around the country.

Sinn Fein achieved a breakthrough, winning its first EU Parliament seat in Ireland and another in Northern Ireland.

Sinn Fein leader Gerry Adams said the double success was a challenge to both the Irish and British governments to make progress on the Northern Ireland peace process.

"The big focus we have to all be involved in -- it's above party politics -- is getting this peace process sorted out and getting it bedded down and moved ahead," he told RTE.

Sinn Fein holds five seats in the Irish national parliament.